The main objective of project 1 is to evaluate the diversity of the ecology and parasite populations related to the epidemiology and clinical findings in order to establish a scientific framework that supports the development of new intervention strategies for malaria elimination in non-Amazonian areas of LA. This goal will be approached through the following specific aims: 1) Study the epidemiology of seasonal malaria and their relationship with parasite population diversity and 2) Identification risk factors associated with malaria transmission in non-Amazonian areas of LA countries. We hypothesize that circulating Plasmodium populations and their dynamics modulate the clinical manifestations and immune responses in the affected populations and that vector bionomics, parasite population diversity, host biology and behavior, household conditions, and local environmental conditions, act simultaneously to determine malaria transmission and risk of infection. The studies proposed for aim 1 are directed to determine the real prevalence and incidence of malaria by considering both symptomatic and asymptomatic individuals living in seasonal areas in LA. This investigation includes community based cohort studies (prospective studies), active surveillance using temporal cross-sectional studies, and hospital based passive surveillance studies. The studies will be carried out in 7 endemic areas of Colombia, Peru, Panama and Guatemala, where a total of 21 sentinel sites will be studied. Studies will be carried out in three phases: 1) Our own census of the selected population from sentinel sites where inhabitants will be registered using a demographic questionnaire and houses coordinates using a GPS system; 2) thick smear and PCR for malaria diagnose in selected sentinels sites and random sampling in order to determine asymptomatic gametocytes carriers; 3) clinical follow-up and thick smear of asymptomatic at two sentinel sites (one in Colombia (Tierralta) and one in Peru (Sulluna). For aim 2 we will a) assess the conditions of antimalarial use in communities where malaria is endemic, including adherence, self-medication and prophylaxis; and (b) study the conditions of use of antimalarials in the public and private health institutions including the availability and suitability to care guides. In this ICEMR program, we will establish a network of sentinel sites that will be selected integrating bio-geographic criteria (vector and ecological conditions) and epidemiological information. Sentinel sites will provide baseline information on malaria ecology and epidemiology with the goal of characterizing parasite and vector populations resilient to control interventions. Such network will allow supporting current efforts directed to develop population models to quantify disease dynamics and malaria risk-maps to support MOH elimination activities.